(in the bible)
In the Douay Version, captain represents several different Hebrew and Latin words.
It is used only for the highest civil officers as in the expressions "captain of my people" (4 Kings), and "let us appoint a captain" (Numbers 14).
Military officers of all grades, however, are thus designated, e.g.: generals; infantry officers; captains of cavalry (2 Par.); commanders of the bodyguard (Genesis 26); officers charged with the organization of newly-levied troops and the order of the camp, and some whose status was not clear but who were later aides-de-camp.
In the New Testament "captain", occurs but once: "for out of thee shall come forth the captain [Our Lord] that shall rule my people Israel" (Matthew 2).
New Catholic Dictionary